<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>viewport适配</title>
    <style>
      * {
        margin: 0;
        padding: 0;
      }
      #box {
        width: 100px;
        height: 100px;
        background-color: red;
      }
    </style>
  </head>
  <body>
    <!-- 
        viewport适配：
            优点: 所量即所得
            缺点: 会导致网页被压缩,里面的内容看不清,尤其是字体
    -->
    <div id="box">测试</div>
  </body>
</html>
